Eraser shield



March 26, 1940. D. s. RICHARDSON ERASER SHIELD Filed Feb.' 7. 193sPatented Mar. Z6, 1940 UNITE stares, rarest ortica l' ApplicationFebruary 7, 1939, Serial No. 255,094 In Great Britain Marchi?, 1938Claims.

This invention relates to erasershields of the kind used by typists inorder that anerror in one or more letters' Whichhave been typed can beyerased without mutilating an adjacent letter.

More particularly, the invention relates to eraser shields ofA the type(hereinafter referred to as the type described) consisting of a thinsheet of material having. one ormore holes or slots which can be placedon the line ofwriting W so that only the lettervor letters, which haveto beerased, are exposed to view throughha hole. Heretofore, shields ofthe type described have been rectangular in shape with rounded corners,

and these shields have been used not only as 5"" eraser shields, butalsol as advertising devices and,

in sorne cases, as visiting cards. When made of Celluloid, it has beenfound by experiencethat the material must not exceed .015" in thickness,otherwise the shields are not lexible'enough to 520 bend round thetypewriter platen, while if 'they areA less than .010, although they areverysatv isfactory with regard to flexibility, the Celluloid is sobrittle that it very easily breaks, rendering the'shields useless afterashort time. Further,

2f the arrangement of the slots has heretofore been quite arbitrary, andthe slots in a] shield have been designed, asto their width, length andshape, with' reference to only one particular letter spacing on atypewriting machine with whichthe shield U was intended 'tobe used. Asthe letter spacing on typewriting machines varies from 12 to the lf 'to8 to the l, it will be appreciated that a shield designed foruse withone spacing may not be'v welly adapted 'to be used with a machine 'of a:rfiA differentA spacing.

An important object of the present invention is to provide an improvedconstruction of eraser shield. of the type described which shall bevmore convenient in use than those v known heretofore, #lo and-in whichthe Vslots are arranged in a predel termined manner with reference tothe centre of the shield. r

According to the invention there is provided an eraser shield of thetype described, wherein a row 45 of slots isfarranged circularly or in acurved path around the central portieri` of the shield,which slots' aresituated nearer lto the periphery than to the center of the shield andeach lies at an acute angle on a 'line radialto the central lpor-r SHtion ofthe shield, so that rotation ofthe shield the center of theshield.4

(Cl. 1Z0-41) Preferably, the shield having a plurality'of slots is soAconstructed that when it is rotated about its centre, each slot willliein turn at its correct position of use for a right-#handed typist, orvif the shield is reversed,v for a left-handed typist.

The slots may be so arranged in spaced relation around themcentre of theshield that the angular distancesbetween them are substantially equalone to another. f

The shield may have'a circular periphery.

Alternatively, the shield may have a polygonal ory substantiallypolygonal periphery of Y regular or irregular shape, but having morethanfour sides. f One embodiment of the invention is Idiagrammaticallyillustrated by way of example in the accompanying drawing, wherein: v

Figure l is a plan view showing one form vof eraser shield provided withslots according tothe invention, and f Figures 2 to 7 illustrate the'slots drawn to a larger scale than that of Figure 1.

. ofeight radii which will be referred to by, and

are markedwith the points of the compass W, SW, S, SE, E, NE, N, NW.There is no aperture yat the `centreof the shield.A Some of the slotsdiffer in size from that of others, and some lie nearer the periphery,of theshield than the others. Theslots Il, I2, I3, land I6 liecentrally on the radii W, SW, S, E and NE, respectively, while thecentresr of the three slots lll, l1 and i8 are displaced angularly a fewdegrees anti-clockwise from the radii SE, N and NW, respectively, andlie respectively on radii ESE, NWN, and WNW. f

A numeral or other index, printed or otherwise applied to the shield, isallotted to .each,slot, which numerals rrun"consecutively from rl to 8,and are so positioned in relation to the slotsthat when the` numeralallottedto a slot `is placed ver-v tically, .that slot is in itsposition of use. Each numeral maybe provided with a mark, such as anarrowI or a diamond surrounding it, for facilitating positioning itvertically byl rotating the shield. In the position of the shield shownin Figure 1 the-numeral 4 is vertical, and the slot i4! isvertical-n itsposition of use. Similarly, when the numerals 1, 2, 3, 5 vand 6 are'placed7-r vertically their slots will be vertical inthe position of use,while, when the numerals 7 and. 8

are vertical, their slots I'I and I8, respectively, will be horizontalin the position of use.

The major and minor axis of each slot make an angle less than 90 withthe respective radius bisecting the slot. Preferably, the angle at whichthe major axis of a slot lies on its radius is between 40" and 50 whenthe slot is used either vertically or horizontally for erasing letterson lines above the bottom of the sheet, but for erasing letters in alineat the bottom of the sheet, the corresponding angle of the vertical slotmay be reduced to to 25. As indicated in Figure 1, the angles which themajor axes of the slot make with the radii passing through their centresare as follows:

Degrees Slots II, I2 and I5 l 45 Slots I3 and I6 22.5 Slot I4 48 SlotI'l 41.5 Slot I8 41 When the slots are inclined at the angles yjustmentioned, it is found that the centre of the slot in the operatingposition for vertical erasing is between 1A," to from the bottom of theshield and itt in the case of a horizontal slot, When the shield has anoverall diameter of 3". When in use, the shield is taken up by theoperator and rotated about its central portion, and the appropriate slotis brought into its correct operating position, whereupon the shield isplaced against the paper for the erasing operation. If the slots arearranged sloping in the direction for use by a right-handed typist, whenthe shield is reversed, it will be found that the slots can be used by aleft-handed typist.

The slots lying on the various radii are shown at the followingdistances from the centre of the shield:

Radii W, SW, S, E and NE at 13% Radius WNW at 151g Radius NWN at 331g"Radius ESE at 11/8 It will be seen that the three slots Il, I8 and I Ilie on their radii respectively successively greater distances from thecentre of the shield when considered in counter-clockwise direction, andat successively lesser distances therefrom when considered in aclockwise direction.

As shown in Figures 2 to 7 the dimensions in inches of the various slotson the 3 shield shown in Figure 1 are as follows:

These dimensions are given by way of example only, and it is to beunderstood that the oval slots for horizontal use may vary from -l to3&1' in length and from tog-'2 in width. Slots for vertical use may varyfrom 3%" to 1% in length and 1/8 to %4 in Width. l

When the shield is polygonal, its sides may be straight or curved and ofany convenient number more than four. The shield illustrated may beregarded as an octagonal ligure, whereof the angles and sides arerounded or curved. The use of a polygon rather than a circle isconvenient in that if flat sides are used, one side for every slot,Whenever one of the flat sides is held parallel to the axis of a platen,a slot Will be situated in its correct position of use. In the exampleillustrated, when the middle curved portion of a side at thebottom ofFigure 1 is situated in the N-S direction, a slot I4 to `the right-handthereof will be situated in its correct position of use.

The (shield may be made of any convenient sheet material, preferablyvulcanised fibre; other materials, such as presspahn, leatheroid, pressboard, Celluloid and metal may, however, be used. The shield,particularly when made of vulcanised fibre, may be provided with aprotective coating, e. g., cellulose lacquer, varnish, casein, methylcellulose, or a water-soluble resin; in some cases, the coating mayconsist of a lining of regenerated cellulose.

Various modifications may be made in the details of form and arrangementof the slots described above. For example, the angular spacing of theradii on which the centres of the slots are situated may vary a fewdegrees from the positions indicated on the drawing. Similarly, the sizeand shapes of the various slots may be modied slightly.

I claim:`

1. An eraser shield of the character described, consisting of a thinsheet of material having `a polygonal periphery with `more than foursides and having a plurality of erasure slots of elongated formationarranged in spaced relation in a substantially circular, endless rowthat surrounds the central portion of the shield and lies nearer to itsperiphery than to its center, each of which slots lies at an acute angleon a, line that is radial to the central portion of the shield andsubstantially bisects one of the sides of the polygon and each slot isdisposed at an acute angle to the respective radial line on which itlies.

2. An eraser shield of the character described, consisting of a thinsheet of material having a plurality of erasure slots of elongatedformation arranged in spaced relation in a substantially circular,endless row that surrounds the central portion of the shield and liesnearer to the periphery than to the center of the shield, each ofwhich'slots is disposed at an acute angle to the line radial to thecentral portion of the shield on which it is situated, and a pluralityof indices that are allotted each to one of the slots, and are sopositioned that when they are placed vertically their allotted slotswill be in the position of use.

3. An eraser shield of the character described, consisting of a thin,substantially circular sheet of material having a plurality of ovalerasure slots arranged in substantially equal spaced relation in asubstantially circular, endless row that surrounds the center of theshield and lies nearer to its periphery than to the center, each ofwhich slots is disposed with the direction of its length at an acuteangle on the line that is radial to the center of the shield on which itlies, and a plurality of indices that are allotted each to one of theslots, and are so positioned that when they are placed vertically, theirallotted slots will be in the position of use.

4. An eraser shield of the character described, consisting of a thinsubstantially circular sheet of material having a plurality of erasureslots vall of elongated formation and all arranged in spaced relation ina substantially circular, endlessl row that surro-undsthe centralportion of the shield and lies nearer to the periphery than to thecenter of the shield, each of which slots is dilsposed at an acute angleof between 20 and 50 to the line radial to the central portion of theshield on which it ssituated.

5. An eraser shield of the character described, consisting of a'thinsheet of materialhaving a plurality o-f erasure slots all of elongatedformation and all arranged in spaced relation in an endless`curved rowthat surrounds the central portion of the shield and lies nearer tothepe.n riphery than to the center of the shield, each of which slots isdisposed at an acute angleto the line radial to the central portion ofthe shield on which it is situated, atl least two of which slots, nextadjacent oneI to another, lie respectively atsuccessively greaterdistance from the Ain

